From 77721bcd00c6b3b8c48b36e6fd18754fcea8f639 Mon Sep 17 00:00:00 2001
From: Jan-Henrik Bruhn <hi@jhbruhn.de>
Date: Fri, 24 Apr 2020 00:38:05 +0200
Subject: [PATCH] Implement gamma correction for volume LED
---
stereo_mix/drivers/leds.h | 5 +-
stereo_mix/resources.cc | 72 +++++++++++++++++++++++++++
stereo_mix/resources.h | 5 ++
stereo_mix/resources/lookup_tables.py | 9 ++++
stereo_mix/resources/resources.py | 2 +
5 files changed, 92 insertions(+), 1 deletion(-)
diff --git a/stereo_mix/drivers/leds.h b/stereo_mix/drivers/leds.h
index 21f0082..eeb638f 100644
--- a/stereo_mix/drivers/leds.h
+++ b/stereo_mix/drivers/leds.h
@@ -1,8 +1,11 @@
#pragma once
+#include "../resources.h"
#include "stm32f0xx_hal_gpio.h"
#include <stm32f0xx_hal.h>
+using namespace stereo_mix;
+
const uint8_t kNumChannels = 4;
static const uint16_t kGpioPins[] = { GPIO_PIN_7, GPIO_PIN_15, GPIO_PIN_13, GPIO_PIN_14 };
@@ -26,7 +29,7 @@ class Leds {
pwm_counter += 2;
for (size_t i = 0; i < kNumChannels; i++) {
- if (intensities[0] && intensities[i] >= pwm_counter) {
+ if (intensities[0] && lut_led_gamma[intensities[i]] >= pwm_counter) {
HAL_GPIO_WritePin(kGpioPorts[i], kGpioPins[i], GPIO_PIN_SET);
} else {
HAL_GPIO_WritePin(kGpioPorts[i], kGpioPins[i], GPIO_PIN_RESET);
diff --git a/stereo_mix/resources.cc b/stereo_mix/resources.cc
index 61a5e35..e5ddd32 100644
--- a/stereo_mix/resources.cc
+++ b/stereo_mix/resources.cc
@@ -3120,5 +3120,77 @@ const uint16_t* lookup_table_u16_table[] = {
lut_right_cos_pan,
};
+const uint8_t lut_led_gamma[] = {
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ 0, 0, 1, 1,
+ 1, 1, 1, 1,
+ 1, 1, 1, 2,
+ 2, 2, 2, 2,
+ 2, 3, 3, 3,
+ 3, 3, 4, 4,
+ 4, 4, 5, 5,
+ 5, 5, 6, 6,
+ 6, 7, 7, 7,
+ 8, 8, 8, 9,
+ 9, 9, 10, 10,
+ 11, 11, 11, 12,
+ 12, 13, 13, 14,
+ 14, 14, 15, 15,
+ 16, 16, 17, 17,
+ 18, 18, 19, 20,
+ 20, 21, 21, 22,
+ 22, 23, 24, 24,
+ 25, 25, 26, 27,
+ 27, 28, 29, 29,
+ 30, 31, 31, 32,
+ 33, 33, 34, 35,
+ 36, 36, 37, 38,
+ 39, 40, 40, 41,
+ 42, 43, 44, 44,
+ 45, 46, 47, 48,
+ 49, 50, 51, 51,
+ 52, 53, 54, 55,
+ 56, 57, 58, 59,
+ 60, 61, 62, 63,
+ 64, 65, 66, 67,
+ 68, 69, 70, 71,
+ 72, 73, 75, 76,
+ 77, 78, 79, 80,
+ 81, 83, 84, 85,
+ 86, 87, 88, 90,
+ 91, 92, 93, 95,
+ 96, 97, 98, 100,
+ 101, 102, 104, 105,
+ 106, 107, 109, 110,
+ 112, 113, 114, 116,
+ 117, 118, 120, 121,
+ 123, 124, 126, 127,
+ 129, 130, 131, 133,
+ 134, 136, 137, 139,
+ 141, 142, 144, 145,
+ 147, 148, 150, 151,
+ 153, 155, 156, 158,
+ 160, 161, 163, 165,
+ 166, 168, 170, 171,
+ 173, 175, 176, 178,
+ 180, 182, 183, 185,
+ 187, 189, 191, 192,
+ 194, 196, 198, 200,
+ 202, 203, 205, 207,
+ 209, 211, 213, 215,
+ 217, 219, 221, 223,
+ 225, 226, 228, 230,
+ 232, 234, 236, 238,
+ 241, 243, 245, 247,
+ 249, 251, 253, 255,
+};
+
+
+const uint8_t* lookup_table_u8_table[] = {
+ lut_led_gamma,
+};
+
} // namespace stereo_mix
diff --git a/stereo_mix/resources.h b/stereo_mix/resources.h
index 1d51b1b..7259056 100644
--- a/stereo_mix/resources.h
+++ b/stereo_mix/resources.h
@@ -44,15 +44,20 @@ typedef uint8_t ResourceId;
extern const uint16_t* lookup_table_u16_table[];
+extern const uint8_t* lookup_table_u8_table[];
+
extern const uint16_t lut_linear_to_exp[];
extern const uint16_t lut_left_sin_pan[];
extern const uint16_t lut_right_cos_pan[];
+extern const uint8_t lut_led_gamma[];
#define LUT_LINEAR_TO_EXP 0
#define LUT_LINEAR_TO_EXP_SIZE 4096
#define LUT_LEFT_SIN_PAN 1
#define LUT_LEFT_SIN_PAN_SIZE 4096
#define LUT_RIGHT_COS_PAN 2
#define LUT_RIGHT_COS_PAN_SIZE 4096
+#define LUT_LED_GAMMA 0
+#define LUT_LED_GAMMA_SIZE 256
} // namespace stereo_mix
diff --git a/stereo_mix/resources/lookup_tables.py b/stereo_mix/resources/lookup_tables.py
index 6fcd8fe..289e4d0 100644
--- a/stereo_mix/resources/lookup_tables.py
+++ b/stereo_mix/resources/lookup_tables.py
@@ -1,5 +1,6 @@
import numpy as np
lookup_tables_u16 = []
+lookup_tables_u8 = []
ADC_RESOLUTION = 4096
OUTPUT_RESOLUTION = 2 ** 16 - 1
@@ -26,3 +27,11 @@ r_pan = np.round(r_pan * OUTPUT_RESOLUTION)
lookup_tables_u16.append(('left_sin_pan', l_pan))
lookup_tables_u16.append(('right_cos_pan', r_pan))
+# led gamma correction
+gamma = 2.1
+max_in = 255
+max_out = 255
+input_vals = np.linspace(0, max_in, num=max_in + 1)
+gamma_correction = ((input_vals / max_in) ** gamma) * max_out + 0.5
+lookup_tables_u8.append(('led_gamma', np.floor(gamma_correction)))
+
diff --git a/stereo_mix/resources/resources.py b/stereo_mix/resources/resources.py
index ab7e0fc..b77eb32 100755
--- a/stereo_mix/resources/resources.py
+++ b/stereo_mix/resources/resources.py
@@ -74,4 +74,6 @@ create_specialized_manager = True
resources = [
(lookup_tables.lookup_tables_u16,
'lookup_table_u16', 'LUT', 'uint16_t', int, False),
+ (lookup_tables.lookup_tables_u8,
+ 'lookup_table_u8', 'LUT', 'uint8_t', int, False),
]